title: Concomitant changes in function tests, breathing pattern And PaCO2 in patients with chronic obstructive pulmonary disease.
abstract: 151 ambulatory male patients with chronic obstructive pulmonary disease have been studied twice, at time intervals ranging from 2 to 36 months (average : 11), to determine the relationships between changes in lung function tests, pattern of breathing and arterial PCO2. This longitudinal analysis confirms the results of cross-sectional studies: variations in PaCO2 seem independent of the evolution of lung function tests (FEV1, VC, FEV1/VC, RV/TLC). Increases in PaCO2 are associated with a decrease in tidal volume and no change in respiratory frequency. These changes in breathing pattern result in a decreased minute ventilation and an increased VD/VT ratio.
mesh_terms: D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure; D012115:Residual Volume; D012119:Respiration; D012129:Respiratory Function Tests
chemical_list: D002245:Carbon Dioxide